SL280DFV Gas Furnace Installation Manual - Lennox

chilled air from entering the furnace (see figure 1). If the
damper is manually operated, it must be equipped to prevent
operation of either the heating or the cooling unit, unless
it is in the full HEAT or COOL setting.
GAS UNIT
Dampers
(open during heating
operation only)
FIGURE 1
AIR HANDLER
Dampers
(open during cooling
operation only)
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Electric
Code, ANSI/NFPA No. 70. The National Electric Code
(ANSI/NFPA No. 70) is available from the following address:
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
NOTE − This furnace is designed for a minimum continuous
return air temperature of 60°F (16°C) or an intermittent
operation down to 55°F (13°C) dry bulb for cases
where a night setback thermostat is used. Return air temperature
must not exceed 85°F (29°C) dry bulb.
The SL280DFV furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms in the
downflow position.
This furnace design has not been CSA International certified
for installation in mobile homes, recreational vehicles,
or outdoors.
Use of Furnace as Construction Heater
Lennox does not recommend the use of SL280DFV units
as a construction heater during any phase of construction.
Very low return air temperatures, harmful vapors and operation
of the unit with clogged or misplaced filters will damage
the unit.
SL280DFV units may be used for heating of buildings or
structures under construction, if the following conditions
are met:
The vent system must be permanently installed per
these installation instructions.
A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
The return air duct must be provided and sealed to the
furnace.
Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
Air filters must be installed in the system and must be
maintained during construction.
Air filters must be replaced upon construction completion.
The input rate and temperature rise must be set per the
furnace rating plate.
One hundred percent (100%) outdoor air must be provided
for combustion air requirements during construction.
Temporary ducting may supply outdoor air to the
furnace. Do not connect duct directly to the furnace.
Size the temporary duct following these instructions in
section for Combustion, Dilution and Ventilation Air in a
confined space with air from outside.
The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction clean−up.
All furnace operating conditions (including ignition, input
rate, temperature rise and venting) must be verified
according to these installation instructions.
General
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the following
general recommendations must be considered
when installing a SL280DFV furnace:
Place the furnace as close to the center of the air distribution
system as possible. The furnace should also be
located close to the chimney or vent termination point.
Do not install the furnace where drafts might blow directly
into it. This could cause improper combustion and unsafe
operation.
Do not block the furnace combustion air openings with
clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
When the furnace is installed in an attic or other insulated
space, keep insulation away from the furnace.
NOTE − The Commonwealth of Massachusetts stipulates
these additional requirements:
Gas furnaces shall be installed by a licensed plumber
or fitter only.
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